The outpatient clinic provides a "well state" group of 90 patients for genetic and pharmacologic studies of persons with Bipolar (manic-depressive) disorders and Unipolar (major depressive) disorders. The clinic also studies treatment response to medications, particularly in Bipolar disorder. There are 23 normal twin pairs and 23 normal volunteers who serve as controls for these studies. We have developed the use of an assay for lithium in parotid saliva as a clinical alternative to blood lithium levels. Eleven Bipolar patients have participated in our study of trihexyphenidyl as an antidepressant. Preliminary results are promising. Three patients have participated in the antidepressant study of pirbuterol.